Nature of Operations and Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($)	3 Months Ended												12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share Basic And Diluted [Line Items]
Net income (loss)	$ 955,348	$ 916,961	$ 507,650	$ 146,180	$ 2,049	$ (1,632,601)	$ (2,193,017)	$ (1,468,300)	$ (1,470,730)	$ (2,052,059)	$ (2,393,275)	$ (1,359,642)	$ 2,526,139	$ (5,291,869)	$ (7,275,706)
Weighted-average common shares and share equivalents outstanding—basic	30,969,157	30,764,694	30,697,391	30,618,097	30,510,587	30,481,168	30,453,455	30,402,397	27,492,670	27,109,787	26,473,938	26,024,288	30,790,258	30,466,063	27,492,670
Weighted-average common shares and share equivalents outstanding—diluted	31,664,178	31,645,696	31,321,259	31,173,815	31,022,148	30,481,168	30,453,455	30,402,397	27,492,670	27,109,787	26,473,938	26,024,288	31,480,241	30,466,063	27,492,670
Net income (loss) per share - Basic	$ 0.03	$ 0.03	$ 0.02	$ 0.00	$ 0.00	$ (0.05)	$ (0.07)	$ (0.05)	$ (0.05)	$ (0.08)	$ (0.09)	$ (0.05)	$ 0.08	$ (0.17)	$ (0.26)
Net income (loss) per share - Diluted	$ 0.03	$ 0.03	$ 0.02	$ 0.00	$ 0.00	$ (0.05)	$ (0.07)	$ (0.05)	$ (0.05)	$ (0.08)	$ (0.09)	$ (0.05)	$ 0.08	$ (0.17)	$ (0.26)
Stock options [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive potential common stock equivalents													689,983	0	0